【作者】 黄瑞；

【导师】 张新访；

【作者基本信息】 华中科技大学 ， 计算机技术， 2019， 硕士

【摘要】 去中心化应用(DApp)基于区块链思想实现,此类应用去除了交易中第三方公信机构,对推动交易方式的变革具有重要意义。资产溯源为DApp的设计重点,此功能可令用户获取任意物品详细信息和流转详情,保证了交易的透明性。现有的溯源应用将物品数据直接存储在区块链中,且应用存在覆盖面窄、交易时延长、链上数据膨胀快等问题。论文基于Fabric网络实现了满足资产溯源需求的DApp,此应用不会导致网络数据快速膨胀,并能保证可靠的溯源操作及物品转移交易功能。对于任何待交易物品的详细信息均采取加密算法生成唯一证据存储在区块链中来证实其真实性,利用区块链的共识机制可保证存储在区块链中的证据不会被任何人修改。区块链中存储的证据唯一对应一批物品,物品的详细信息通过merkle树形结构进行组织,此结构可保证对任何物品信息的修改均会导致当前批次物品对应的证据与区块链上的证据不一致,这一修改可被区块链上所有用户感知,从而达到防伪目的,同时物品的详细信息被存储在链外数据库中,这能有效降低区块链数据膨胀速率。为了实现物品溯源,论文采用了未花费输出(UTXO)模型,此模型可将一批物品的流转详情保存在一笔交易中,因为区块链账本保存了所有交易,所以用户可通过遍历交易获取流转详情进行任意物品的溯源。测试结果表明,应用的各个功能模块可满足正常的溯源需求,在高并发交易时应用的平均时延基本处于可控范围,系统吞吐率能够满足生产环境中的需要,因此本应用的设计思想对区块链资产溯源研究具有借鉴意义。更多还原

【Abstract】 Decentralized application(DApp)is based on the idea of blockchain.Such applications remove the third-party public trust institutions in the transaction and are of great significance to promote the change of trading methods.Asset traceability is the design focus of DApp.This feature allows users to obtain detailed information and routing details of any item,ensuring transparency of the transaction.The existing traceability application stores the item data directly in the blockchain,and the application has problems such as narrow coverage,extended transaction time,and rapid data expansion on the chain.Based on the Fabric network,the paper implements DApp that meets the requirements of asset traceability.This application will not cause rapid expansion of network data,and can ensure reliable traceability operation and item transfer transaction function.For the details of any items to be traded,an encryption algorithm is used to generate unique evidence stored in the blockchain to verify its authenticity.The consensus mechanism of the blockchain ensures that the evidence stored in the blockchain will not be modified by anyone.The evidence stored in the blockchain uniquely corresponds to a batch of items,and the detailed information of the item is organized by the merkle tree structure,which ensures that the modification of any item information will lead to the evidence corresponding to the current batch of items and the blockchain.The evidence is inconsistent.This modification can be perceived by all users in the blockchain to achieve anti-counterfeiting purposes.At the same time,the detailed information of the items is stored in the out-of-chain database,which can effectively reduce the rate of blockchain data expansion.In order to achieve item traceability,the paper uses the unspent transaction output(UTXO)model,which saves the transfer details of a batch of items in a transaction,because the blockchain account saves all transactions,so users can obtain by traversing the transaction.Transfer details to trace the source of any item.The test results show that the functional modules of the application can meet the normal traceability requirements.The average delay applied in high concurrent transactions is basically in the controllable range,and the system throughput can meet the needs in the production environment.Therefore,the design idea of this application is The traceability research of blockchain assets has reference significance.更多还原